There may be additional files that you want removed
when the -c option is used,
but which SCons doesn't know about
because they're not normal target files.
For example, perhaps a command you invoke
creates a log file as
part of building the target file you want.
You would like the log file cleaned,
but you don't want to have to teach
SCons that the command
"builds" two files.

You can use the Clean function to arrange for additional files
to be removed when the -c option is used.
Notice, however, that the Clean function takes two arguments,
and the second argument
is the name of the additional file you want cleaned
(foo.log in this example):

The first argument is the target with which you want
the cleaning of this additional file associated.
In the above example,
we've used the return value from the
Command function,
which represents the
foo.out
target.
Now whenever the
foo.out target is cleaned
by the -c option,
the foo.log file
will be removed as well: